perf probe: Add basic module support

Add basic module probe support on perf probe. This introduces "--module
<MODNAME>" option to perf probe for putting probes and showing lines and
variables in the given module.

Currently, this supports only probing on running modules.  Supporting off-line
module probing is the next step.

e.g.)
[show lines]
 # ./perf probe --module drm -L drm_vblank_info
<drm_vblank_info:0>
      0  int drm_vblank_info(struct seq_file *m, void *data)
      1  {
                struct drm_info_node *node = (struct drm_info_node *) m->private
      3         struct drm_device *dev = node->minor->dev;
 ...
[show vars]
 # ./perf probe --module drm -V drm_vblank_info:3
Available variables at drm_vblank_info:3
        @<drm_vblank_info+20>
                (unknown_type)  data
                struct drm_info_node*   node
                struct seq_file*        m
[put a probe]
 # ./perf probe --module drm drm_vblank_info:3 node m
Add new event:
  probe:drm_vblank_info (on drm_vblank_info:3 with node m)

You can now use it on all perf tools, such as:

        perf record -e probe:drm_vblank_info -aR sleep 1
[list probes]
 # ./perf probe -l
probe:drm_vblank_info (on drm_vblank_info:3@drivers/gpu/drm/drm_info.c with ...

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101021101341.3542.71638.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

7 files changed, 239 insertions, 69 deletions

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 148c178a35a..62de1b7f4e7 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -16,9 +16,9 @@ or
 or
 'perf probe' --list
 or
-'perf probe' --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'
+'perf probe' [options] --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'
 or
-'perf probe' [--externs] --vars='PROBEPOINT'
+'perf probe' [options] --vars='PROBEPOINT'
 
 DESCRIPTION
 -----------
@@ -33,6 +33,11 @@ OPTIONS
 --vmlinux=PATH::
         Specify vmlinux path which has debuginfo (Dwarf binary).
 
+-m::
+--module=MODNAME::
+        Specify module name in which perf-probe searches probe points
+        or lines.
+
 -s::
 --source=PATH::
         Specify path to kernel source.
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index bdf60cfdf70..2e000c068cc 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -57,6 +57,7 @@ static struct {
         struct perf_probe_event events[MAX_PROBES];
         struct strlist *dellist;
         struct line_range line_range;
+        const char *target_module;
         int max_probe_points;
 } params;
 
@@ -162,8 +163,8 @@ static const char * const probe_usage[] = {
         "perf probe [<options>] --del '[GROUP:]EVENT' ...",
         "perf probe --list",
 #ifdef DWARF_SUPPORT
-        "perf probe --line 'LINEDESC'",
-        "perf probe [--externs] --vars 'PROBEPOINT'",
+        "perf probe [<options>] --line 'LINEDESC'",
+        "perf probe [<options>] --vars 'PROBEPOINT'",
 #endif
         NULL
 };
@@ -214,6 +215,8 @@ static const struct option options[] = {
                    "file", "vmlinux pathname"),
         OPT_STRING('s', "source", &symbol_conf.source_prefix,
                    "directory", "path to kernel source"),
+        OPT_STRING('m', "module", &params.target_module,
+                   "modname", "target module name"),
 #endif
         OPT__DRY_RUN(&probe_event_dry_run),
         OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
@@ -278,7 +281,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
                         usage_with_options(probe_usage, options);
                 }
 
-                ret = show_line_range(&params.line_range);
+                ret = show_line_range(&params.line_range, params.target_module);
                 if (ret < 0)
                         pr_err("  Error: Failed to show lines. (%d)\n", ret);
                 return ret;
@@ -291,6 +294,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
                 }
                 ret = show_available_vars(params.events, params.nevents,
                                           params.max_probe_points,
+                                          params.target_module,
                                           params.show_ext_vars);
                 if (ret < 0)
                         pr_err("  Error: Failed to show vars. (%d)\n", ret);
@@ -310,6 +314,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
         if (params.nevents) {
                 ret = add_perf_probe_events(params.events, params.nevents,
                                             params.max_probe_points,
+                                            params.target_module,
                                             params.force_add);
                 if (ret < 0) {
                         pr_err("  Error: Failed to add events. (%d)\n", ret);
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 78575796d5f..b397c038372 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -215,6 +215,16 @@ struct symbol *map_groups__find_function_by_name(struct map_groups *self,
         return map_groups__find_symbol_by_name(self, MAP__FUNCTION, name, mapp, filter);
 }
 
+static inline
+struct symbol *machine__find_kernel_function_by_name(struct machine *self,
+                                                     const char *name,
+                                                     struct map **mapp,
+                                                     symbol_filter_t filter)
+{
+        return map_groups__find_function_by_name(&self->kmaps, name, mapp,
+                                                 filter);
+}
+
 int map_groups__fixup_overlappings(struct map_groups *self, struct map *map,
                                    int verbose, FILE *fp);
 
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 82b0976e205..3b6a5297bf1 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -74,10 +74,9 @@ static int e_snprintf(char *str, size_t size, const char *format, ...)
 static char *synthesize_perf_probe_point(struct perf_probe_point *pp);
 static struct machine machine;
 
-/* Initialize symbol maps and path of vmlinux */
+/* Initialize symbol maps and path of vmlinux/modules */
 static int init_vmlinux(void)
 {
-        struct dso *kernel;
         int ret;
 
         symbol_conf.sort_by_name = true;
@@ -91,33 +90,61 @@ static int init_vmlinux(void)
                 goto out;
         }
 
-        ret = machine__init(&machine, "/", 0);
+        ret = machine__init(&machine, "", HOST_KERNEL_ID);
         if (ret < 0)
                 goto out;
 
-        kernel = dso__new_kernel(symbol_conf.vmlinux_name);
-        if (kernel == NULL)
-                die("Failed to create kernel dso.");
-
-        ret = __machine__create_kernel_maps(&machine, kernel);
-        if (ret < 0)
-                pr_debug("Failed to create kernel maps.\n");
-
+        if (machine__create_kernel_maps(&machine) < 0) {
+                pr_debug("machine__create_kernel_maps ");
+                goto out;
+        }
 out:
         if (ret < 0)
                 pr_warning("Failed to init vmlinux path.\n");
         return ret;
 }
 
+static struct symbol *__find_kernel_function_by_name(const char *name,
+                                                     struct map **mapp)
+{
+        return machine__find_kernel_function_by_name(&machine, name, mapp,
+                                                     NULL);
+}
+
+const char *kernel_get_module_path(const char *module)
+{
+        struct dso *dso;
+
+        if (module) {
+                list_for_each_entry(dso, &machine.kernel_dsos, node) {
+                        if (strncmp(dso->short_name + 1, module,
+                                    dso->short_name_len - 2) == 0)
+                                goto found;
+                }
+                pr_debug("Failed to find module %s.\n", module);
+                return NULL;
+        } else {